ANSYS nCode DesignLife™ for 13.0 ANSYS® Workbench™

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© 2011 ANSYS, Inc. 8/29/11
ANSYS nCode
DesignLife
for
13.0 ANSYS®
Workbench
Jeff Mentley
HBM-nCode

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Introduction
© 2011 ANSYS, Inc. 8/29/11
Agenda
What is Fatigue and Why is it important
Approaches for Fatigue
ANSYS nCode DesignLife overview
What is new for ANSYS 13.0 DesignLife SP1
Questions

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ANSYS® nCode DesignLife
© 2011 ANSYS, Inc. 8/29/11
Integrated within
ANSYS Workbench
13 to provide a
leading solution for
advanced fatigue
analysis.

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Fatigue is:
Failur e under a r epeat ed or
ot herw ise var ying load
w hic h never r eac hes a level
suf fic ient t o c ause failur e in
a single applic at ion.
T he init iat ion and g r ow t h of a
c r ac k , or g r ow t h of a pr eex
ist ing defec t , unt il it
r eac hes a c rit ic al size.
The progressive and localized
structural damage that occurs
when a material is subjected to
cyclic loading.
© 2011 ANSYS, Inc. 8/29/11
What is Fatigue?
Stress
Stress
Strain
Time

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© 2011 ANSYS, Inc. 8/29/11
Early Failures
1808 Trevithick's “Catch-me-who-can”

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© 2011 ANSYS, Inc. 8/29/11
Present Day Fatigue Failure
1999 – ICE high-speed trail derailed at Eschede,
Germany
– Hit bridge pillar - 100 k illed
– Ear l y w heel design c aused
vibrat ions
– New w heel design
– Based upon st r eet c ar design
– Not t est ed at high speed
befor e ser vic e
– Com plet e pr ot ot ypes never
t est ed
– Cr ash findings
– Caused by c r ac k in w heel
– Dynam ic , repet it ive for c es
had not been ac c ount ed for
in design
– Design lac k ed an adequat e

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© 2011 ANSYS, Inc. 8/29/11
Why is it Important ?
Why do we need to do Fatigue Analysis?
• “...Between 80 - 90% of all structural failures
occur through a fatigue mechanism…”
• “...The estimated annual cost of fracture and
fatigue to the US was 4.4% of GDP…”
“The Economic Effects of
Fracture in the United States,” National
Bureau of Standards, U.S. Department of
Commerce, Gaithersburg, MD, Special
Publication 647-2, 1983.

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© 2011 ANSYS, Inc. 8/29/11
Fatigue Analysis Process
Loading
Environment
Geometry
Material
Properties
Fatigue Analysis
• Stress-life
• Strain-life
• Crack growth
Post-processing
optimization
Life
Fatigue is a statistical,
not deterministic,
phenomenon.

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Fatigue Analysis: Stress-Life
(SN)
SN is also known as “High
Cycle Fatigue” or “Nominal
Stress Approach”
Elastic stress history used
to determine life
May be applied to either
material or component
Used extensively for
welded joints and nonmetallics
Suitable for lives greater
than 1e4 cycles
Well established, Familiar,
Large amount of material
data available, Simple
loadings can be analyzed
as a hand calc.
© 2011 ANSYS, Inc. 8/29/11
Stress, centners/zoll2
800
600
400
200
Wöhler circa 1850
Smooth shoulder
Sharp shoulder
104 105 106
Cycles, N

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Fatigue Analysis: Strain-Life
(EN)
EN is also known as
“Low Cycle Fatigue”,
“Crack Initiation” or
“Local Strain Approach”
Elasto-plastic strain
history used to
determine life
Local plasticity can be
estimated from fully
elastic FE analysis or
computed directly in
ANSYS
Suitable for low and
high cycle fatigue
Cycle counting and
© 2011 ANSYS, Inc. 8/29/11
ε
Plastic (Low Cycle
Fatigue Line)
Elastic (High Cycle
Fatigue Line)
N

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© 2011 ANSYS, Inc. 8/29/11
Fatigue Analysis: Crack
Growth
Crack growth known as
crack propagation, or
fracture mechanics
Predicts cycle by cycle
crack growth
Used in aerospace Damage
Tolerance analysis
Determine impact of known
or suspected flaws
Crack

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© 2011 ANSYS, Inc. 8/29/11
ANSYS® nCode DesignLife
ANSYS
Workbench®
Engineering
Data
Mechanical
Materials
Stresses
Loads
DesignLife

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ANSYS® nCode DesignLife
– nCode OEM Par t ner ship
– nCode DesignLife
– Advanc ed Fat igue
Anal ysis
– Pr oc ess Orient at ion
– Ease of Use
– Wor k benc h Int e g r at ion
– DesignLife Syst em s
– Design Par am et er s
– Mat erial libr ar y
© 2011 ANSYS, Inc. 8/29/11

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ANSYS® nCode DesignLife
Streamlining - the Features
Virtual
Engineering Process
© 2011 ANSYS, Inc. 8/29/11
– Powerful Fatigue
Analysis Technology
– Integrated
Reporting and
Process
Encapsulation
– Fast, Expandable,
and Scalable

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ANSYS® nCode DesignLife
- Features
Intuitive and easy to use
software for perfor m ing
fat igue anal ysis of finit e
elem ent m odels.
Efficiently analyze lar ge finit e
elem ent m odels and c om plet e
usa ge sc hedules.
Wide range of fatigue analysis
capabilities inc luding st r esslife,
st r ain-life, m ult i-ax ial,
w eld anal ysis, vir t ual shak er
t able, and m or e.
Single environment for bot h
Test and CAE dat a.
Ex t ensive material database
© 2011 ANSYS, Inc. 8/29/11

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ANSYS® nCode DesignLife -
Capabilities
YS nCode DesignLife has an extensive scope of fatigue capabilities…
– St r ain-Life (aut om at ed m ult i-ax ial
c or r ec t ions)
– St r ess-Life (single, m ult i-c ur ve,
Haigh diagram s)
– Cr ac k Gr ow t h (LEFM)
– Seam w elds and spot w elds
– High t em per at ure fat igue
– V ibr at ion fat igue (shak er sim ulat ion)
– V ir t ual St r ain ga ge
– Com plet e dut y c yc les / flight
spec t r um s
– Mult iple r uns in a single analysis
– Mult i-pr oc essor enabled for fast
result s
© 2011 ANSYS, Inc. 8/29/11
Finit e Elem ent result s
suppor t ed
– St at ic (linear
super posit ion)
– Tr ansient
– Modal
– Frequenc y Response
– Linear & Non-linear
Finit e Elem ent solver s
suppor t ed
– ANSYS
– Abaqus
– Nast ran
– LS-Dyna

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ANSYS® nCode DesignLife
- Benefits
– Perfor m vir t ual dur abilit y assessm ent up fr ont t o
r educ e relianc e on physic al t est and avoid c ost l y
design and t ooling c hanges
– Perfor m sm ar t er and quic k er physic al t est s by
sim ulat ing fir st
– Design dur abilit y int o your pr oduc t s and reduc e
w ar r ant y c laim s
– St andar dize anal ysis pr oc esses t o im prove
c onsist enc y and qualit y
– Aut om at e pr oc esses t o bet t er ut ilize engineer s’
t im e and w or k load
– Assess m or e design opt ions, c onsider m or e
r ealist ic loading c ondit ions and m ore c onfident l y
r educ e c ost and w eight
© 2011 ANSYS, Inc. 8/29/11

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© 2011 ANSYS, Inc. 8/29/11
ANSYS® 13 nCode
DesignLife SP1
– Support for Named Selections
– New state engine to manage DesignLife system
updates
– DesignLife processes saved with results
– FKM mean stress with multicurve SN
– Material map import deactivate
– Seam weld enhancements
– BS7608 and Eurocode 3 weld analysis

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Questions
© 2011 ANSYS, Inc. 8/29/11
ANSYS ® nCode
DesignLife

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Jeff Mentley
HBM - nCode
Tel: +1.248.945.4368
jeff.mentley@ncode.com
Ray Browell
ANSYS, Inc.
Tel: +1.724.514.3070
Ray.Browell@ansys.com
© 2011 ANSYS, Inc. 8/29/11
ANSYS ® nCode
DesignLife
Thank you!